This invention relates generally to arming devices for munitions and, more particularly, to arming devices and related methods of operation which selectively permit a munition to the jettisoned or otherwise discharged bomb in a safe condition or in an armed condition.
A variety of military aircraft carry bombs or other related munitions which are mounted to bomb racks that are attached to the aircraft. It is normally a requirement that the crew aboard the aircraft be able to reliably control the instances in which the bombs are discharged from their corresponding bomb racks in an armed condition, as opposed to being discharged in a safe condition in which the bombs will not detonate. As is well-known, unintentional armed discharges of bombs from aircraft can pose a significant danger to the lives of non-combatants and allied combatants. Conversely, unintentional safe discharges can thwart essential military objectives. Consequently, it is highly desirable and typically necessary to have special arming devices connected to the bombs.
As is conventional, a separate arming device is connected to each bomb by a single wire that is ordinarily attached to the fuse of the bomb. The wire itself is then played out by the bomb as the bomb is jettisoned or otherwise discharged. In the case of a safe discharge, the arming device releases the wire once the wire has exerted a predetermined amount of pulling force on the arming device. However, for an armed discharge, the arming device retains the wire as the bomb is discharged and the resultant force acting on the fuse arms the bomb. According to a number of currently effective military specifications, for a safe discharge an arming device should release the wire at a threshold pulling force of ten to twelve pounds. These specifications also provide that the fuse should not be activated until it experiences a threshold activation force of a certain predetermined magnitude (typically, about thirty pounds) greater than the aforementioned threshold pulling force. Further, the arming device should be able to selectively hold the wire against a force of at least 150 pounds or even substantially higher. For example, in certain cases, the device may have to hold the arming wire against a combined static and dynamic force of at least 1,500 pounds.
A variety of arming devices which release the wire in response to a force which is of insufficient magnitude to arm the munition are known. By way of example, arming devices of this nature are described in my previous patents, U.S. Pat. No(s). 4,088,055 and 4,212,225. However, unwanted armed discharges of bombs have continued to occur. More particularly, from time to time, the fuse of the bomb is activated even though the force acting on the fuse is less than the threshold activation force. Moreover, in a safe discharge condition, the arming device may malfunction by retaining the wire altogether or by not releasing the wire until the pulling force exerted on the arming device has exceeded the aforementioned threshold activation force. The latter of these two situations may occur because the fluid or slip stream around the aircraft may act on the bomb in a manner that augments the pulling force on the wire beyond the threshold activation force.
It should, therefore, be appreciated that there exists a definite need for a versatile arming device which more reliably regulates the discharge of a munition in a safe as well as an armed condition and which tends to minimize malfunctioning of the arming device.